Those are rejected blocks.
Look at the summary screen. It shows 85 (86) for the 5870, 68 (69) for the first 5970, and 107 (110) for the second 5970. Those match up with the 1, 1 and 3 showing in the device tabs.
Actually, the (bracketed numbers) in Guiminer are an hourly running total (current 60 minute window total) that rises and falls.......